Jacketed cable with powder layer for enhanced corrosion and environmental protection

Abstract

A corrosion-resistant electric cable has a metallic conductor, a polymeric insulating jacket surrounding the metallic conductor, and a corrosion-inhibiting powder comprised of a hydrophobic material disposed between the metallic conductor and the insulating jacket. The corrosion-inhibiting powder may be comprised of a mixture of a hydrophobic fumed silica powder and a hydrophobic polyethylene powder.

That which is claimed is: 
     
       1. A corrosion-resistant cable comprising at least one metallic conductor, a polymeric insulating jacket surrounding said conductor, and a corrosion-inhibiting hydrophobic powder disposed between said metallic conductor and said insulating jacket and coating said at least one metallic conductor, said powder serving to prevent any moisture which might enter the cable from traveling longitudinally along the cable beneath said jacket in corrosive contact with said metallic conductor. 
     
     
       2. A corrosion-resistant cable as claimed in claim 1, wherein said corrosion-inhibiting hydrophobic powder is comprised of flowable, smooth-surfaced hydrophobic particles. 
     
     
       3. A corrosion-resistant cable according to claim 1, wherein said corrosion-inhibiting hydrophobic powder comprises hydrophobic fumed silica. 
     
     
       4. A corrosion-resistant cable as claimed in claim 3, wherein said hydrophobic fumed silica has been surface coated with a hydrophobic agent. 
     
     
       5. A corrosion-resistant cable as claimed in claim 4, wherein said hydrophobic agent is a hydrophobic polyfunctional silane. 
     
     
       6. A corrosion-resistant cable comprising at least one metallic inner conductor, a dielectric material surrounding the inner conductor, a metallic shielding conductor surrounding the dielectric material and the inner conductor, a polymeric insulating jacket surrounding said shielding conductor and forming a protective outer covering for the cable, and a corrosion-inhibiting hydrophobic powder disposed between said metallic shielding conductor and said insulating jacket and coating said metallic shielding conductor, said powder serving to prevent any moisture which might enter the cable from traveling longitudinally along the cable beneath said jacket in corrosive contact with said metallic shielding conductor. 
     
     
       7. A corrosion-resistant cable comprising a metallic inner conductor, a polyolefin dielectric material surrounding the inner conductor, a metallic shielding tape surrounding the dielectric material and the inner conductor, and an open wire braid surrounding the metallic shielding tape so that a plurality of shallow pockets are formed adjacent the metallic shielding tape between the individual strands of the wire braid, the cable further comprising a corrosion-inhibiting hydrophobic powder coating said metallic shielding tape and dispersed in the pockets formed in said wire braid and a polyolefin insulating jacket surrounding said wire braid so that said corrosion-inhibiting powder is trapped in the pockets formed therein, said powder serving to prevent any moisture which might enter the cable from traveling longitudinally along the cable beneath said jacket in corrosive contact with said metallic shielding tape and said wire braid. 
     
     
       8. A corrosion-resistant cable according to claim 6 or 7, wherein said corrosion-inhibiting hydrophobic powder comprises hydrophobic fumed silica. 
     
     
       9. A corrosion-resistant cable according to claim 6 or 7, wherein said corrosion-inhibiting hydrophobic powder comprises a mixture of hydrophobic fumed silica powder and hydrophobic polyethylene powder. 
     
     
       10. A method of making a corrosion-resistant cable having at least one metallic conductor, said method comprising coating the metallic conductor with a corrosion-inhibiting hydrophobic powder and then applying a polymeric insulating jacket around the powder-coated metallic conductor to form a protective covering which traps the hydrophobic powder as a layer against the metallic conductor. 
     
     
       11. A method according to claim 10 wherein the step of coating the metallic conductor with a corrosion-inhibiting hydrophobic powder comprises applying to the conductor hydrophobic fumed silica powder. 
     
     
       12. A method according to claim 10, wherein the step of coating the metallic conductor comprises tumbling a corrosion-inhibiting powder around the cable, which powder is a relatively dense powder that uniformly coats the conductor. 
     
     
       13. A method according to claim 10, wherein the step of coating the metallic conductor comprises applying to the conductor a hydrophobic fumed silica powder and a hydrophobic polyethylene powder. 
     
     
       14. A method of imparting corrosion resistance to a cable having a metallic conductor comprising the steps of advancing a cable having an exposed metallic conductive surface along a predetermined path of travel to and through a coating station; contacting the exposed metallic conductive surface with a corrosion-inhibiting hydrophobic powder and forming a powder coating around the metallic conductor; and advancing the powder coated cable from the coating station to an extruder and extruding a jacket of polymeric insulating material around the powder coated metallic conductor. 
     
     
       15. A method according to claim 14, wherein the step of contacting the metallic conductive surface with a corrosion-inhibiting hydrophobic powder comprises applying to the conductive surface a hydrophobic fumed silica powder. 
     
     
       16. A method according to claim 14, wherein the step of contacting the metallic conductive surface with a corrosion-inhibiting hydrophobic powder comprises tumbling a corrosion-inhibiting powder around the cable, which powder is a relatively dense powder that uniformly coats the conductor. 
     
     
       17. A method according to claim 14, wherein the step of contacting the metallic conductive surface with a corrosion-inhibiting hydrophobic powder comprises applying to the surface a hydrophobic fumed silica powder and a hydrophobic polyethylene powder. 
     
     
       18. A corrosion-resistant cable comprising at least one metallic conductor, a polymeric insulating jacket surrounding said conductor, and a corrosion-inhibiting hydrophobic powder disposed between said metallic conductor and said insulating jacket, said corrosion-inhibiting hydrophobic powder comprising a mixture of hydrophobic fumed silica and hydrophobic polyethylene powder, said corrosion-inhibiting hydrophobic powder serving to prevent any moisture which might enter the cable from traveling longitudinally along the cable beneath said jacket in corrosive contact with said metallic conductor.